Air filtration system

ABSTRACT

An air filtration system that reduces positive and/or negative resistance by eliminating duct work to and from the to-be-filtered room. The air filtering system forms a common wall with the to-be-filtered room permitting dirty air to move easily and quickly through to the cleaning process. Through the use of vertical baffles and reverse pulsed jets, debris is easily and efficiently collected in drawers or trays. Because of the modular design of the invention, it is easily placed on a trailer and transported to a locale which is to be cleaned within a flexible room (i.e. bridges, building exteriors, airplanes, etc.).

BACKGROUND OF THE INVENTION

This invention relates generally to abrasive blasting and moreparticularly to air filtration systems used in conjunction with abrasiveblasting rooms.

Maintaining a clean environment is critical in many industries. Airborne debris has detrimental affects both upon products and workers inthe area. This makes the collection of dust and other airborne particlesgenerated from abrasion blasting, removing of dry products, or similardust generating activities, essential for the well being of workers andthe environment. In many industrial areas, the Federal EnvironmentalProtection Agency has set strict standards for the air quality in orderto protect workers and the environment.

Within the abrasive blasting industry, the need for clean air iscritical since dirty air: (i) obstructs visibility which may lead todamage to the substrate being cleaned and (ii) may require moreexpensive and cumbersome breathing equipment to protect the operator.

Suspended debris in the abrasive blasting industry consists not only ofdust from spent abrasive medium, but also from the removed paints andcoatings, many of which are hazardous to an operator's health.

Another important consideration is the portability of equipment. Withthe increasing need for air filtration at abrasive blast sites such asbridges, exteriors of buildings, dry docked boats, and the like, theneed to have a truly portable system is paramount.

In many situations, the paint or coating to be removed must be handledwith care since many contain heavy metals such as lead or chrome whichresults in the residue from these coating being classified as hazardousor toxic waste. Air borne contaminants are no exception. These air bornecontaminants must be filtered out before the air is exhausted into theenvironment.

To provide for a clean working environment, the typical solution is toprovide a cyclone wind turbine to draw air, via duct work, from theto-be-cleaned room. This provides a negative pressure room to encouragethe debris to stay within the system and not leave the room.

An example of such a system is described by U.S. Pat. No. 4,789,387,entitled "Dust Collector" issued to Nemesi et al. on Dec. 6, 1988.

Typical movement of air within an abrasive blast room is in the3000-8000 Cubic Feet per Minute (CFM). To achieve this movement andcleaning of the air, motors on the order of one horse or more arerequired. Motors having this capability use an exorbitant amount ofelectrical energy and thereby reduces the efficiency of the abrasiveblasting system.

Furthermore, these systems are designed for a specific room understandardized conditions. Little flexibility is provided since toincrease the CFM capacity of the system requires major redesign andreconstruction of the cyclone, ducts, and bag houses.

To provide for a more efficient use of the electrical energy, and alsogive a little flexibility, some air cleaning systems utilize wall units.These modular units fit into a wall of the room. Such apparatus arecommercially sold by Torit, a division of Donaldson Company, Inc. andare associated with Environmental Control Booths.

The Torit apparatus eliminates the duct work normally associated withdust control and provides for louvers between the to-be-cleaned room andthe dust collection apparatus. The dust collection apparatus usesstandard air filtration cartridges. Air is drawn directly through thelouvers, through the filter cartridges, and then exhausted into theatmosphere.

Although the Torit apparatus does come in three different sizes,modification to accommodate different air flow requirements iscumbersome and often impossible since large air flow requirements wouldrequire long banks of units and motors with complex motor start controlsystems. Further, the Torit apparatus is designed to provide onlyminimal cleaning capability since only a small portal for air flow isprovided. Even more restrictive, the Torit apparatus is not easily madeportable.

Without portability, the Torit apparatus is totally unsuitable for manycritical applications which arise in the modern world.

It is clear from the foregoing that an efficient, portable, andversatile air cleaning system does not exist.

SUMMARY OF THE INVENTION

The present invention provides for an air filtration system that Reducespositive and/or negative air flow resistance by eliminating duct workfrom the room to the filtering system. The filtering system forms acommon wall with the to-be-filtered room permitting the dirty air tomove easily and quickly through to the cleaning process. Through the useof vertical baffles and reverse jets, debris is easily and efficientlycollected in drawers or trays located at the bottom of the filtrationsystem. Because of the modular design of the invention, the filtrationsystem is easily placed on a trailer and transported to remote sites.Further the portable filtration system uses a portable flexible shroudto assist in cleaning items at the site (i.e. bridges, buildingexteriors, etc.).

Although the present discussion relates to the removal of dust, paintparticles, and other related matter, those of ordinary skill in the artreadily recognize that the present invention is applicable for cleaningany suspended dry matter from a room's air.

the air filter system of the present invention forms one of the walls tothe to-be-cleaned room. To the maximum extent possible, the air filtercommunicates with the to-be-cleaned room. In the preferred embodiment,this level of communication is over fifty percent of the wall space.

Located between the air filter system and the to-be-cleaned room is abaffle system arranged in a vertical fashion. The vertical bafflesprovide for a visual and physical barrier between the room and the airfilter system; but, the baffles readily permit debris laden air to passinto the air filter system.

The vertical baffles are important since their structure discourages theformation of a film of debris on their surfaces. As the debris passesthrough, some of the debris does tend to stick to the surfaces, yet theforce of gravity tends to dislodge this debris, maintaining the bafflesin a relatively clean state.

Air flowing through the baffles enter a "dirty air plenum" within theair filter system which is used to collect the debris. This section ofthe air filtration system has extending into it, several air filtrationcartridges through which the air flows and which clean the air ofsuspended debris.

This debris is periodically removed from the filters through the use ofreverse pulse jets known to those of ordinary skill in the art. One suchreverse pulse jet is described in U.S. Pat. No. 4,578,092, entitled"Method and Apparatus for Improving the Operation of a Dust Collector"issued to Klimczak on Mar. 25, 1986, and incorporated hereinto byreference.

At the bottom of the "dirty air plenum" with its attendant air filtercartridges, and also below the baffles, is located a debris removalapparatus. In the preferred embodiment this debris removal apparatus isa series of drawers which are removable from outside the air filterapparatus. These drawers collect the debris which falls from thebaffles, and also the debris ejected from the filter cartridges due tothe reverse pulsed jets.

In an alternative environment, a collection of hoppers replaces thedrawers and are used to collect the fallen debris for immediate,constant, or periodic removal either manually or automatically. Those ofordinary skill in the art recognize various structures which work inthis context.

One of the most important aspects of the preferred embodiment of theinvention is that the structure of the air filter system permits thesystem to be quickly and easily adjusted to obtain the desired air flowfor the cleaning required by the specific situation. The driving motoris positioned at the top of the blower permitting the motor to replacedeasily. This facilitates the altering of the air flow characteristics ofthe air filtration system.

As example, a particular system is customizable to anything from 3000CFM to 20,000 CFM by adjusting the motor size. This replacement of themotor permits optimal matching of the air filtration system to theto-be-cleaned room.

Another aspect of the preferred embodiment is the modular approach inwhich the air filter system is portable and is easily attached, throughzippers, clasps, or the like, to a flexible room or shroud. Thisflexible room or shroud, constructed of such material as canvas orplastic sheeting, is adaptable for use in exterior environments forcleaning planes, buildings, bridges, boats, and other such equipment andedifices.

By placing the filter system on a trailer, the filter system is easilytransported to the site and used there until the job is completed. Theflexible room is disassembled, loaded onto the trailer, and the entiresystem is transported to a new site for a different job.

The invention, together with various embodiments thereof will be morefully described by the following drawings and their accompanyingdescriptions.

DRAWINGS IN BRIEF

FIG. 1 is a perspective view of the preferred embodiment of theinvention.

FIG. 2 is a top view of the preferred embodiment of the baffles used inthe embodiment of FIG. 1.

FIG. 3 is a side view of a transportable embodiment of the invention.

DRAWINGS IN DETAIL

FIG. 1 is a perspective view of the preferred embodiment of theinvention. Housing member 10 is composed of two basic sections: a dirtyair plenum 16 and a clean air plenum 15. Dirty air plenum 16communicates with the abrasive blast room (not shown) via baffles 14which extend substantially to the floor. Baffles 14 form a section ofone wall of the abrasive blast room and permit debris laden air to enterdirty air room 16.

Several air filter cartridges 13 extend from the clean air plenum 15into the dirty air plenum 16. Air passing through the air filtercartridges 13 is cleaned of any suspended debris. This debris isperiodically purged from the surface of the air filter cartridges via areverse pulse jet/8.

Although the present invention utilizes a reverse pulse jet, those ofordinary skill in the art readily recognize various alternative methodsto removed trapped debris from the surface of air filter cartridgesincluding but not limited to shakers and the like.

Air filtration cartridges 13 are secured in place by a bolt and nutarrangement 18 that extends through the center of air filtrationcartridge 13. This arrangement permits easy removal of the airfiltration cartridge as illustrated by 13B.

In one embodiment of the invention, the top hole in which aircommunicates through the air filter cartridge 18 with the clean airplenum 15 is closed via a solid plug 6. This technique of pluggingselected air filter cartridges is used when the full capability of theair filter system is not required or desired.

Blower 11 is powered by motor 12 which exhausts air from clean air room15 as indicated by arrow 9C. Debris laden air enters the system throughbaffles 14 as shown by arrow 9A; passes through the air filter cartridge13 and enters the clean air plenum 15 as indicated by arrow 9B.

In this manner, dirty air is drawn into the air filtration system andclean air is exhausted into the environment. Motor 12 is removable fromthe blower via bolts and collar 7.

The debris collected by the air filter system collects on the air filtercartridges 13 and also tends to collect on the baffles 14. The baffles14, being vertical in nature, utilize natural gravity to dislodge andrelease the deposited debris. This debris, together with the debris fromthe air filter cartridges falls to the bottom of the dirty air plenumand collects in drawers 19A, 19B, and 19C.

These drawers are periodically removed and cleaned of the collecteddebris. The debris so collected includes spent media, dust from theabrasive blasting operation, and removed material.

In one embodiment of the invention, bin type hoppers are used in lieu ofdrawers 19A, 19B, and 19C. Use of hoppers permit the automatic removalof fallen debris.

The dimensions of housing 10 need not be adjusted to fit theto-be-cleaned room's size. A wall of the to-be-cleaned room is commonwith a wall of the air filtration system. By simple adjustment to themotor 12 and blower 11, the proper air movement, from 3,000 CFM to over9,000 CFM is easily obtained.

FIG. 2 is a top view of the preferred embodiment of the baffles firstillustrated in FIG. 1.

The baffle system is composed of a series of generally widened "U"shaped channels which are interlocked as indicated by U's 20A, 20B withU's 21A, 21B, and 21C. This interlocking permits air flow, as indicatedby arrows 22, to pass between the U's but provides a physical and visualbarrier between the to-be-cleaned room and the air filtration system.

The vertical nature of the baffles is important since it is thisarrangement which permits the easy and automatic cleaning of collecteddebris, without causing resitatnce to the air flow into the dirty airplenum.

In one embodiment of the invention, the baffles are equipped with ashaker which further facilitates the removal of collected debris intothe underlying drawers.

Although the present invention utilizes generally "U" shaped channels,those of ordinary skill in the art readily recognize various othershapes which lend themselves to the objective of the present inventionincluding baffles having interlocking sinus curve shapes or evenoverlapping planar panels.

FIG. 3 is a side view of a transportable version of the presentinvention.

An air filtration system 36 as discussed relative to FIG. 1 includinghousing 10, blower 11 and motor 12, is mounted onto trailer 32 fortransportation to the abrasive blasting site. Also mounted on trailer 32is generator 30 which provides power to the air filtration system, andrack 31 which holds the flexible and collapsable building 33 whendisassembled.

Collapsable building 33 attaches to the air filtration system 10 throughsnaps, zippers, or other techniques known to those of ordinary skill inthe art. An internal skeleton 35 provides support while tension line 34maintains the flexible room 33 in an upright position.

This embodiment of the invention provides for easy transportation to theblast site (such as where aircraft are to be cleaned) and easy use. Notethat the air filtration system 36 and generator 30 are permanentlymounted on trailer 32.

The reduction of positive and negative resitance achieved by eliminatingduct work, allows higher volumes of air to be filtered using much lowerhorsepower motors than units of conventional design.

It is clear from the foregoing that the present invention provides for avastly improved air filtration system that is easily modified forspecific requirements and is easily transported to address on-siteabrasive blasting.

What is claimed is:
 1. An air filtration system for cleaning air withina room comprising:a) a housing, one side of said housing forming acommon wall with said room, said housing having a lower first sectionand an upper second section; b) baffles disposed between the firstsection of said housing and said room, said baffles substantiallycovering said common wall; c) a chamber formed in the second sectionhaving at least three air filtration cartridges extending into saidfirst section; d) blower means attached to an exterior portion of saidhousing, said blower means communicating with said second section fordrawing air from said second section and exhausting the air exterior tosaid housing; e) a motor located external to said housing for drivingsaid blower means; and, f) at least two drawers located substantially atthe bottom of said housing, said drawers being operable from an exteriorposition to said housing, said drawers being positioned to receivefalling debris from said baffles and from said first section of saidhousing.
 2. The air filtration system according to claim 1 wherein saidbaffles include vertically arranged, interlocking, U-shaped baffles. 3.The air filtration system according to claim 2 further including areverse air pulse mechanism positioned to drive debris from said atleast three air filtration cartridges into said first section.
 4. Theair filtration system according to claim 3 wherein said motor isremovable and replaceable with a replacement motor having differentcapabilities then the original motor.
 5. The air filtration systemaccording to claim 3 wherein at least one of said at least three airfiltration cartridges is blocked to prevent airflow therethrough.
 6. Afiltration system for cleaning air within a room comprising:a) ahousing, one side of said housing forming a common wall with said room,said housing having a lower first section and an upper second section;b) baffles disposed between the first section of said housing and saidroom, said baffles extending over more than half of said common wall; c)a chamber formed in the second section having at least three airfiltration cartridges extending into said first section; d) blower meansattached to an exterior portion of said housing, said blower meanscommunicating with said second section for drawing air from said secondsection and exhausting the air exterior to said housing; e) a motor fordriving said blower means; and, f) at least one drawer locatedsubstantially at the bottom of said housing, said drawer being operablefrom an exterior position to said housing, said drawer being positionedto receive falling debris from said baffles and from said first sectionof said housing.
 7. The filtration system according to claim 6 whereinsaid baffles include vertically arranged, interlocking, U-shapedbaffles.
 8. The filtration system according to claim 7 further includinga reverse air pulse mechanism positioned to drive debris from said atleast three air filtration cartridges into said first section.
 9. Thefiltration system according to claim 8 wherein said motor is removableand replaceable with a replacement motor having different capabilitiesthen the original motor.
 10. The filtration system according to claim 8wherein at least one of said at least three air filtration cartridges isblocked to prevent airflow therethrough.
 11. The filtration systemaccording to claim 8 further including means for operator removal ofdebris from said first section and said baffles.
 12. An air filtrationsystem for cleaning air within a flexible room comprising:a) a housing,one side of said housing attachable to and forming a common wall withsaid flexible room, said housing having a lower first section and anupper second section; b) baffles disposed between the first section ofsaid housing and said room, said baffles substantially covering saidcommon wall; c) a chamber formed in the second section having at leastthree air filtration cartridges extending into said first section; d)blower means attached to an exterior portion of said housing, saidblower means communicating with said second section for drawing air fromsaid second section and exhausting the air exterior to said housing; e)a motor for driving said blower means; and, f) at least two drawerslocated substantially at the bottom of said housing, said drawers beingoperable from an exterior position to said housing, said drawers beingpositioned to receive falling debris from said baffles and from saidfirst section of said housing.
 13. The air filtration system accordingto claim 12 wherein said baffles include vertically arranged,interlocking, U-shaped baffles.
 14. The air filtration system accordingto claim 13 further including a reverse air pulse mechanism positionedto drive debris from said at least three air filtration cartridges intosaid first section.
 15. The air filtration system according to claim 14wherein said motor is removable and replaceable with a replacement motorhaving different capabilities then the original motor.
 16. The airfiltration system according to claim 14 wherein at least one of said atleast three air filtration cartridges is blocked to prevent airflowtherethrough.
 17. A portable blast room comprising:a) a flexible room;b) an air filtration system having,1) a housing, one side of saidhousing attaching to and forming a common wall with said flexible room,said housing having a lower first section and an upper second section,2) baffles disposed between the first section of said housing and saidroom, said baffles substantially covering said common wall, 3) a chamberformed in the second section having at least three air filtrationcartridges extending into said first section, 4) blower means attachedto an exterior portion of said housing, said blower means communicatingwith said second section for drawing air from said second section andexhausting the air exterior to said housing, 5) a motor for driving saidblower means; and, 6) at least two drawers located substantially at thebottom of said housing, said drawers being operable from an exteriorposition to said housing, said drawers being positioned to receivefalling debris from said baffles and from said first section of saidhousing; and, c) electrical generation means for supplying electricalenergy to said motor.
 18. The portable blast room according to claim 17wherein said baffles include vertically arranged, interlocking, U-shapedbaffles.
 19. The portable blast room according to claim 18 furtherincluding a reverse air pulse mechanism positioned to drive debris fromsaid at least three air filtration cartridges into said first section.20. The portable blast room according to claim 19 wherein said motor isremovable and replaceable with a replacement motor having differentcapabilities then the original motor.
 21. The portable blast roomaccording to claim 19 wherein at least one of said at least three airfiltration cartridges is blocked to prevent airflow therethrough. 22.The portable blast room according to claim 19 further including atrailer having mounted thereon said air filtration system and saidelectrical generation means, and for transportation of said flexibleblast room.